<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>test::basic_stream::async_read_some</title>
<link rel="stylesheet" href="../../../../../../../doc/src/boostbook.css" type="text/css">
<meta name="generator" content="DocBook XSL Stylesheets V1.79.1">
<link rel="home" href="../../../index.html" title="Chapter 1. Boost.Beast">
<link rel="up" href="../boost__beast__test__basic_stream.html" title="test::basic_stream">
<link rel="prev" href="read_some/overload2.html" title="test::basic_stream::read_some (2 of 2 overloads)">
<link rel="next" href="write_some.html" title="test::basic_stream::write_some">
</head>
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
<table cellpadding="2" width="100%"><tr>
<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../../boost.png"></td>
<td align="center"><a href="../../../../../../../index.html">Home</a></td>
<td align="center"><a href="../../../../../../../libs/libraries.htm">Libraries</a></td>
<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td>
<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td>
<td align="center"><a href="../../../../../../../more/index.htm">More</a></td>
</tr></table>
<hr>
<div class="spirit-nav">
<a accesskey="p" href="read_some/overload2.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../boost__beast__test__basic_stream.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="write_some.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a>
</div>
<div class="section">
<div class="titlepage"><div><div><h5 class="title">
<a name="beast.ref.boost__beast__test__basic_stream.async_read_some"></a><a class="link" href="async_read_some.html" title="test::basic_stream::async_read_some">test::basic_stream::async_read_some</a>
</h5></div></div></div>
<p>
          <a class="indexterm" name="idm44861286319904"></a>
        </p>
<p>
          Start an asynchronous read.
        </p>
<h6>
<a name="beast.ref.boost__beast__test__basic_stream.async_read_some.h0"></a>
          <span class="phrase"><a name="beast.ref.boost__beast__test__basic_stream.async_read_some.synopsis"></a></span><a class="link" href="async_read_some.html#beast.ref.boost__beast__test__basic_stream.async_read_some.synopsis">Synopsis</a>
        </h6>
<pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span>
    <span class="keyword">class</span> <a href="../../../../../../../doc/html/boost_asio/reference/MutableBufferSequence.html" target="_top"><span class="emphasis"><em>MutableBufferSequence</em></span></a><span class="special">,</span>
    <span class="keyword">class</span> <span class="identifier">ReadHandler</span>  <span class="identifier">BOOST_ASIO_DEFAULT_COMPLETION_TOKEN_TYPE</span><span class="special">&gt;</span>
<a href="../../../../../../../doc/html/boost_asio/reference/asynchronous_operations.html#boost_asio.reference.asynchronous_operations.automatic_deduction_of_initiating_function_return_type" target="_top"><span class="emphasis"><em>DEDUCED</em></span></a>
<span class="identifier">async_read_some</span><span class="special">(</span>
    <span class="identifier">MutableBufferSequence</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">buffers</span><span class="special">,</span>
    <span class="identifier">ReadHandler</span> <span class="special">&amp;&amp;</span><span class="identifier">handler</span> <span class="identifier">BOOST_ASIO_DEFAULT_COMPLETION_TOKEN</span> <span class="identifier">executor_type</span><span class="special">);</span>
</pre>
<h6>
<a name="beast.ref.boost__beast__test__basic_stream.async_read_some.h1"></a>
          <span class="phrase"><a name="beast.ref.boost__beast__test__basic_stream.async_read_some.description"></a></span><a class="link" href="async_read_some.html#beast.ref.boost__beast__test__basic_stream.async_read_some.description">Description</a>
        </h6>
<p>
          This function is used to asynchronously read one or more bytes of data
          from the stream. The function call always returns immediately.
        </p>
<h6>
<a name="beast.ref.boost__beast__test__basic_stream.async_read_some.h2"></a>
          <span class="phrase"><a name="beast.ref.boost__beast__test__basic_stream.async_read_some.parameters"></a></span><a class="link" href="async_read_some.html#beast.ref.boost__beast__test__basic_stream.async_read_some.parameters">Parameters</a>
        </h6>
<div class="informaltable"><table class="table">
<colgroup>
<col>
<col>
</colgroup>
<thead><tr>
<th>
                  <p>
                    Name
                  </p>
                </th>
<th>
                  <p>
                    Description
                  </p>
                </th>
</tr></thead>
<tbody>
<tr>
<td>
                  <p>
                    <code class="computeroutput"><span class="identifier">buffers</span></code>
                  </p>
                </td>
<td>
                  <p>
                    The buffers into which the data will be read. Although the buffers
                    object may be copied as necessary, ownership of the underlying
                    buffers is retained by the caller, which must guarantee that
                    they remain valid until the handler is called.
                  </p>
                </td>
</tr>
<tr>
<td>
                  <p>
                    <code class="computeroutput"><span class="identifier">handler</span></code>
                  </p>
                </td>
<td>
                  <p>
                    The completion handler to invoke when the operation completes.
                    The implementation takes ownership of the handler by performing
                    a decay-copy. The equivalent function signature of the handler
                    must be:
                  </p>
<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="keyword">void</span> <span class="identifier">handler</span><span class="special">(</span>
    <span class="identifier">error_code</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">ec</span><span class="special">,</span>           <span class="comment">// Result of operation.</span>
    <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">bytes_transferred</span>   <span class="comment">// Number of bytes read.</span>
<span class="special">);</span>
</pre>
                  <p>
                    Regardless of whether the asynchronous operation completes immediately
                    or not, the handler will not be invoked from within this function.
                    Invocation of the handler will be performed in a manner equivalent
                    to using <code class="computeroutput"><span class="identifier">net</span><span class="special">::</span><span class="identifier">post</span></code>.
                  </p>
                </td>
</tr>
</tbody>
</table></div>
<h6>
<a name="beast.ref.boost__beast__test__basic_stream.async_read_some.h3"></a>
          <span class="phrase"><a name="beast.ref.boost__beast__test__basic_stream.async_read_some.remarks"></a></span><a class="link" href="async_read_some.html#beast.ref.boost__beast__test__basic_stream.async_read_some.remarks">Remarks</a>
        </h6>
<p>
          The <code class="computeroutput"><span class="identifier">async_read_some</span></code> operation
          may not read all of the requested number of bytes. Consider using the function
          <code class="computeroutput"><span class="identifier">net</span><span class="special">::</span><span class="identifier">async_read</span></code> if you need to ensure that
          the requested amount of data is read before the asynchronous operation
          completes.
        </p>
</div>
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
<td align="left"></td>
<td align="right"><div class="copyright-footer">Copyright © 2016-2019 Vinnie
      Falco<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
      </p>
</div></td>
</tr></table>
<hr>
<div class="spirit-nav">
<a accesskey="p" href="read_some/overload2.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../boost__beast__test__basic_stream.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="write_some.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a>
</div>
</body>
</html>
